Further Delineation of the ALG9-CDG Phenotype

Abstract

ALG9-CDG is one of the less frequently reported types of CDG. Here, we summarize the features of six patients with ALG9-CDG reported in the literature and report the features of four additional patients. The patients presented with drug-resistant infantile epilepsy, hypotonia, dysmorphic features, failure to thrive, global developmental disability, and skeletal dysplasia. One patient presented with nonimmune hydrops fetalis. A brain MRI revealed global atrophy with delayed myelination. Exome sequencing identified a novel homozygous mutation c.1075G>A, p.E359K of the ALG9 gene. The results of our analysis of these patients expand the knowledge of ALG9-CDG phenotype.

Keywords: ALG9-CDG; Congenital disorders of glycosylation; Epilepsy; Hydrops fetalis; Skeletal dysplasia; Whole exome sequencing.

Fig. 1

Photographs of the index case showing craniofacial dysmorphism (partial aplasia cutis congenita of the scalp, hypotelorism, broad base of nose, upturned nose, big mouth, prominent maxilla, large ears), inverted widely spaced nipples, abnormal distribution of fat at the buttocks, cutis marmorata, and broad thumbs

Fig. 2

Pedigree of the family. The index case is indicated by an arrow